New amphoteric surfactants containing a 2‐hydroxyalkyl group: I preparation and properties of N‐(2‐hydroxyethyl)‐N‐(2‐hydroxyalkyl)‐β‐alanines

A series of new amphoteric surfactants, sodium salts of N‐(2‐hydroxyethyl)‐N‐(2‐hydroxyalkyl)‐β‐alanines (Na‐HAA) was prepared by adding methyl acrylate to N‐(2‐hydroxyalkyl)‐ethanolamine and subsequent saponification. Neutralization with HCl gave N‐(2‐hydroxyethyl)‐N‐(2‐hydroxyalkyl)‐β‐alanines, and the addition of ethylene oxide to Na‐HAA gave oxyethylated drivatives. The structures of these compounds prepared were confirmed by infrared spectra, proton magnetic resonance spectra, elementary analyses, etc. Solubility in water, surface tension, foaming power, and critical micelle concentration were determined.